Sickle cell disease effects the African American population. Its acute manifestations include pain crisis involving bones, the priapism, acute chest syndrome, strokes, acute renal or hepatic disease. Most commonly, patients are hospitalized with bone pain crisis requiring intervenous pain medications for several days. These painful episodes interfere with the normal life and function of the patients. The study is designed to assessed a safety and tolerability of repeated exposure to FLOCOR in patients with vaso-occlusive pain crisis of sickle cell disease. FLOCOR is a trade name for purified poloxamer 188. This polymer coats the red blood cells negating their surface electrical charge such that red cells will not adhere to each other or to the vascular endothelium. It also decreases the blood viscosity. FLOCOR will likely help in reducing the duration and the severity of pain. Its clinical effectiveness in sickle cell pain crisis is being evaluated in a randomized placebo controlled trial. This trial has enrolled 134 patients. The total number of patients to be enrolled is 224. The current proposed study will be an open label safety extension study of the above study. Side effects in the 134 patients enrolled to date in the placebo controlled trial are minimal and may include hyperbilirubinemia and fever. The side effects, if any, are reversible on withdrawal of the drug. The proposed safety study will enroll 30 patients at six centers. The patients will have either participated in the Phase III Multicenter study that is ongoing or they would have been ineligible for that study. The dose of FLOCOR is 100 mg/kg given IV over one hour, followed by 30 mg/kg per hr for 47 hours intravenously. The patients may receive a maximum of six courses of FLOCOR within a period of one year from enrollment on the study. Patients ages 10 and less than 65 years of ages with confirmed sickle cell disease will be enrolled. At the time of each treatment, patients will be experiencing acute pain typical of sickle cell disease crisis requiring hospital admission. The patients must meet all the eligibility criteria prior to each treatment on this protocol. The safety, tolerability, and sickle cell disease related events will be monitored.